Answer:
C. Descriptive research
Explanation:
According to my study on the different types of research methods, I can say that based on the information provided within the question the type of research that they are conducting is called a Descriptive Research Method. This method focuses on describing different types of characteristics of the population or phenomenon that is being studied. This can be said because they are describing a small population of the truck drivers and their preferences.
I hope this answered your question. If you have any more questions feel free to ask away at Brainly.